Mechanical power hammer



March 13, 1934. H. scHwoB 1, 2

MECHANICAL POWER HAMMER Filed Aug. 15, 1932 Patented Mar. 13, 1934.

TES

STA

PATENT OFFICE Application August 15,

9 Claims.

The objection of my invention is to provide a mechanical power hammerwhich is simple, durable and comparatively inexpensive to manufacture.

A further object is to provide a power hammer, preferably of portableconstruction, which is of the mechanical type, as distinguished from thepneumatic type.

Still a further object is to provide a mechanical power hammer fordigging, drilling, tamping, crushing and riveting operations, which mayalso be used for breaking rock, cement and the like, the hammer itselfbeing readily adapted to receive dififerent tools for these variousoperations.

Still a further object is to provide a hammer construction in which thehammer is driven me chenically from a source or power such as anelectric motor, a gasoline engine or the like, the hammer being drivenat a high rate of reciprocation from the source of power and acting muchin the same manner as a pneumatic hammer, the structure beingparticularly adapted to perform any operations which pneumatic hammersare adapted to perform.

Still a further object is to provide a hammer construction in which ahammer is reciprocated through resilient connections from a cross head,the reciprocations being imparted to the cross head by a crank shaft andconnecting rod driven from a source of rotating power.

Still a further object is to provide means for rotating the tool whichis being used so that besides imparting a hammering movement to it, itcan be'rotated for drilling operations and the like.

With these and other objects in view my invention consists in theconstruction, arrangement and combination of the various parts oi mydevice, whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claims and illustrated in theaccompanying drawing, in which:

Figure l is a front elevation of my mechanical power hammer.

Figure 2 is a vertical sectional view on the line 2--2 of Figure l.

Figure 3 is a rear elevation of the invention.

Figure 4 is a vertical sectional view on the line 1-4 of Figure 2showing the operation of the hammer;- and Figure 5 is a horizontalsectional view on the line 5-5 of Figure 2 showing details oiconstruction.

On the accompanying drawing I have used the reference numeral is toindicate a hammer tube.

1932, Serial No. 628,860

Within the hammer tube 10, I provide a reciprocable hammer element 12. Iprovide an electric motor 14 for reciprocating the hammer element. 12 inthe following described manner, although it will be obvious that othersources of power can be provided, such as a small internal combustionengine mounted in place of the motor 14.-

The motor 14 is mounted on a base 16, which in turn is secured to theupper end of the hammer tube 10. Through a belt connection 18 the motor1 rotates a crank shaft 20. The crank shaft'20 is journalled in bearings22 which are supported in a transverse sleeve 24 welded or otherwisesecured to the hammer tube 10. v

A crank disc 26 is mounted on the crank shaft and is provided with acrank pin 28. A guide bar 30 is mounted longitudinally of and supportedon the hammer tube 10 and a cross head A is reciprocable therealong.

The cross head A has perforated bearing flanges 32 surrounding the guidebar so and has ends 34 which are arranged on opposite sides of thehammer tube 10. A connecting rod 36 has its ends pivoted to the crankpin 28 and the cross head A respectively. From the description of theforegoing parts, it will be obvious that rotation of the crank shaft 20will be converted into reciprocating movement of the cross head A. Thestroke of the cross head A may be varied by placing the crank pin 28 inany desired opening 28a therefor in the crank disc 26. These openingsare at different distances from the crank shaft 213.

Reciprocation oi the cross head A is trans mitted to the hammer element12 by springs 38 and a link re. The link to is slldable through arectangular opening 42 which extends through the center of the hammerelement 12. The hammer tube 10 is provided with slots as, through whichthe link extends. The ends of the link are perforated and likewise theends of the cross head A are perforated for the ends of the springs 38to hook into.

An anvil element id is loosely mounted in the lower end of the hammertube 10. It receives the impacts of the hammer element 12 when in itsposition shown in Figure 4. These impacts are transmitted to a tool 48,or any other tool which might be inserted into the angular bore so orthe anvil element 46.

v With respect to the operation of the hammer element, when the crankpin 28 starts upward on its travel it is going slowly at first, awayfrom the anvil and is going most rapidly when it is in a positionhorizontal with respect to the crank higher than the crank pin tends tomake it go, thereby increasing the length of the stroke of the hammerelement.

The crank pin then starts to descend on the other side of the crankshaft, slowly at first until it is again horizontal when it is going atits fastest speed. This gives a corresponding downward jerk to'thehammer element which is somewhat arrested by the tension of the springsso that as the crank pin descends it brings the hammer element down withthe speed not only of the descending crank pin but also of the reflexactior. of the springs and the blow of the hammer element is actuallydelivered when the crank pin is at the bottom of its stroke but thehammer element is farther down as illustrated in Figure 4, the springspermitting this. The anvil arrests the blow of the hammer element, whichwould swing on downthe hammer barrel (if the anvil were not there) untilthe springs could fully arrest it.

The element 46 has a flange 52 which normally rests against'the lowerend of the hammer tube 10 when the tool 48 is held against the work tobe done, the hammer element 12 at each impact causing the flange to bedriven away from the tube.

In Figures 2 and 3 I. have shown a tool 48a, which may be used forhammering or crushing operations. It will be obvious that other tools,such as cold chisels and the like, may be substituted for either thetool 48 or 48a. Such tools would have angular shanks of the same crosssection as the bore 50 so as to prevent their rotation relative thereto,yet permit and facilitate insertion and removal of the tools in the samemanner as now done in connection with pneumatic hammers.

During some operations it is desirable to permit the tools to rotate, asthey will naturally do on their own account. During other operations itis desirable to positively rotate the tools. To accomplish rotation, Iprovide the following described mechanism:

A sleeve 54 is screw threaded on the lower end of the hammer tube 10. Itis provided with a flange 58. A rotatable plate 5 8 is positioned belowit and is held in the position shown by a gear which engages the top ofthe flange 56 and which is bolted by bolts or the like 62 to the plate58.

The plate 58 has a pair of key-like projections 64 which interflt withkey-ways 66 formed in the anvil element 46. Thus the plate 58 and the.gears 60 are rotatable relative to the sleeve 54 and carry the anvilelement with them.

For rotating the gears 60, I provide a shaft 68 suitably supported forrotation on the hammer tube 10 and having a spiral gear connection at'70 and 72 with the crank shaft 20' and a pinion 74 to mesh with thecrank 60 Thus rotation of the crank shaft 20 will impart somewhat slowerrotation to the plate 58 and the anvil element 48 as well as to the toolassociated therewith.

The rotating device need not be used if such rotation is not desired.The sleeve'54 can be unscrewed from the lower end of the hammer tube 10so that the assembly'of sleeve, plate 58 and gear 60 can beentirelyremoved when it is not desired to rotate the tool. 7

when an electric motor is used in connection with my hammer structure, asuitable switch,

I have shown handles 76 for the convenience of the operator in handlingthe structure and the switch can be located on one of these. When asmall internal combustion engine is used as the source of power, anidler pulley for tightening the belt 18 can be provided, the belt beingnormally loose enough to permit rotation .of the engine withoutimparting rotation to the crank shaft 20.

These changes, as well as others, may be made in the construction andarrangement of the parts of my device without departing from the realspirit and purpose of my invention, and it is my for impartingreciprocations to said hammer element comprising a crank shaft, a guidelongitudinally of said tube and mounted exterior thereof, a cross headreciprocable'therealong, a connecting rod connection between said crankshaft and said cross head, said cross head having ends on opposite sidesof said hammer tube and resilient connections between said ends and saidhammer element.

2. A power hanimer structure comprising a hammer tube, an anvil in oneend thereof, a hammer element reciprocable in said tube and means forimparting reciprocations to said hammer element comprising a crankshaft, a guide longitudinally of saidtube and mounted exterior thereof,a cross head reciprocable therealong, a connecting rod connectionbetween said crank shaft and said cross head, said-cross head havingends on opposite sides of said hammer tube, ears extending from saidhammer element and springs connecting said ends of said cross head withsaid ears. 3. A power hammer structure comprising a hammer tube, ananvil in one end thereof, a hammer element reciprocable in said tube andmeans for imparting reciprocations to said hammer element comprising acrank shaft, a guide longitudinally of said tube and mounted exteriorthereof, a cross head reciprocable therealong, a connecting rodconnection between said crank shaftand said cross head, said cross headhaving ends on opposite sides of said hammer tube, said hammer elementhaving a slot therethrough, a bar slidable through said slot and springsconnecting the ends of said bar with the ends of said cross head.

4. A power hammer structure comprising a hammer tube, an anvil in oneend thereof, a hammer element reciprocable in said tube and means forimparting reciprocations to said hammer element comprising a crankshaft, a guide longitudinally of said tube and mounted exterior thereof,a cross head reciprocable therealong, a connecting rod connectionbetween said crank shaft and said cross head, said cross head havingends on opposite sides of said hammer tube, resilient connectionsbetween said ends and said hammer element, a rotatable plate mounted onsaid hammer tube and slidably and non-rotatably connected with saidanvil and means for operatively connecting said rotatable plate withsaid crank shaft forrotating the former from the, latter.

5..A powerhammer structure comprising a through, a

hammer guide, an anvil at-one end thereof, a

hammer element reciprocable along said guide and means for impartingreciprocation to said hammer element comprising a crank shaft, a crosshead reciprocable longitudinally of said guide, a connecting rodconnection between said crankshaft and said cross head, said cross headhaving ends on opposite sides of said hammer guide, said hammer elementhaving a slot therebar 'slidable through said slot, and springsconnecting the ends of said car with the ends of said cross head.

SJA power hammer structure comprising a hammerguide, an anvil at one endthereof, a hammer element reciprocable alongsaid guide and means forimparting reciprocation to said hammer element comprising a crank shaft,a cross head reciprocabie longitudinally of said guide, a connecting rodconnection between said crank shaft and said cross head, said cross headhaving ends on opposite sides of said hammer 'guide, resilient.connections between said ends and said hammer element, a rotatable platemounted on said hammer guide and slidably and non-rotatably connectedwith said anvil, and means for operatively connecting said rotatableplate with said crank shaft for rotating the former from the latter.

'7. A power hammer structure comprising a her tube, an anvil in one endthereof, a hammer element reciprocable in said tube and means forimparting reciprocations to said hammer element comprising a crankshaft, a guide longitudinally; oi said tube and mounted exteriorthereof, a cross head reciprocable therealong, a

connecting rod connection between said crank,

shaft and said cross head, said cross head having ends on opposite sidesof said hammer tube, resilient connections between said ends and saidrotating it upon rotation connection between said rotating hammerelement, a d rotatable means operatively connected with said crank shaftand slidably and non-rotatablyconnected with said anvil for of saidcrank shaft.

8. A device of the class described comprisin an impact element guide, animpact element reciprocable along said guide and means for impartingreciprocation to said impact element comprising a rotating shaft, across head reciprocabie longitudinally of said'guide, an operative shaftand said cross head for imparting reciprocations to said cross head,said-cross head having ends on opposite sides of said guide andresilient connectingmeans between said ends and said impact element,said connecting means extending through said impact element and slidabletherethrough to equalize the tension of said means on said; impactelement. 1

9. A device of the class described-comprising an impactoelement guide, atool in one end thereof, an impact element reciprocable along said guideand means for imparting reciprocation to said impact element comprisinga rotating shaft, a cross headreciprocable longitudinally of said guide,an operative connection between said rotating shaft and said cross headfor imparting reciprocations to said cross head, said cross head havingends on opposite sides of said guide, resilient connecting means betweensaid ends and said impact element, said connecting means extendingthrough said impact element and slidable therethroughto equalize thetension of said means on said impact element and rotatable meansoperatively connected with said rotating 11o shaft and slidably andnon-rotatably connected with said tool for rotating it upon rotation ofsaid rotating t.

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